New report of Craspedacusta sowerbii (Lankester, 1880) medusae in Belgium

Abstract

The jellyfish Craspedacusta sowerbii (Lankester, 1880) is known to be an invasive species in freshwater worldwide, except in Antarctica. In Belgium, C. sowerbii was first recorded in 1939 by Damas in the River Meuse. Since then, few further Belgian observations of this species have been made. Here, we report the presence and determine the gender of C. sowerbii medusae in an artificial pond in Forrières, in southern Belgium. This is the first record of this species in the province of Luxembourg. Our findings suggest that the population consists exclusively of females.